package com.twotiger.and.util;

/**
 * 
 * @Description: TODO(这里描述这个类的作用) 
 * @Author douxy
 * @Date 2015年7月9日 下午1:26:43
 */
//TODO rename
public class Pointsdistance {
    private final static double EARTH_RADIUS = 6378137.0;

    public static double point2m(double lat_a, double lng_a, double lat_b, double lng_b) {
        double radLat1 = (lat_a * Math.PI / 180.0);
        double radLat2 = (lat_b * Math.PI / 180.0);
        double a = radLat1 - radLat2;

        double b = (lng_a - lng_b) * Math.PI / 180.0;
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1)
                                           * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000) / 10000;
        return s;
    }
}
